The use of $Layout and subtemplates

Question is whether or not it is possible to use $Layout multiple times in a Page.ss for example. I want to insert "page type specific code" in multiple locations of the Page.ss file - not just the conventional use of $Layout to determine the content area template code by page type but also, for example, parts of the <head> area.

I realise that using $Layout to do this isn't probably the best why but I don't know another way in SS.

Perhaps there is a way to use <% include %> statements conditionally based on Page Type? E.g. <if pagetype == blahblah> or something?

I actually also tried to create a new "Layout-like thing" by creating a directory called "Head", putting a page type specific .ss file in there, and referencing $Head in my root Page.ss file. This didn't seem to work. I guess Layout/$Layout is a hardcoded built in function?